On Fri, Sep 07, 2018 at 05:30:23PM -0700, Joe Perches wrote: > On Fri, 2018-09-07 at 14:29 +0200, Thierry Reding wrote: > > On Tue, Aug 28, 2018 at 10:52:53AM -0500, Rob Herring wrote: > > > In preparation to remove the node name pointer from struct device_node, > > > convert printf users to use the %pOFn format specifier. > > > > > > Cc: Frank Rowand <frowand.list@xxxxxxxxx> > > > Cc: Andrew Lunn <andrew@xxxxxxx> > > > Cc: Florian Fainelli <f.fainelli@xxxxxxxxx> > > > Cc: devicetree@xxxxxxxxxxxxxxx > > > Cc: netdev@xxxxxxxxxxxxxxx > > > Signed-off-by: Rob Herring <robh@xxxxxxxxxx> > > > --- > > > drivers/of/device.c | 4 ++-- > > > drivers/of/of_mdio.c | 12 ++++++------ > > > drivers/of/of_numa.c | 4 ++-- > > > drivers/of/overlay.c | 4 ++-- > > > drivers/of/platform.c | 8 ++++---- > > > drivers/of/unittest.c | 12 ++++++------ > > > 6 files changed, 22 insertions(+), 22 deletions(-) > > > > > > diff --git a/drivers/of/device.c b/drivers/of/device.c > > > index 5957cd4fa262..daa075d87317 100644 > > > --- a/drivers/of/device.c > > > +++ b/drivers/of/device.c > > > @@ -219,7 +219,7 @@ static ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len > > > return -ENODEV; > > > > > > /* Name & Type */ > > > - csize = snprintf(str, len, "of:N%sT%s", dev->of_node->name, > > > + csize = snprintf(str, len, "of:N%pOFnT%s", dev->of_node, > > > dev->of_node->type); > > > tsize = csize; > > > len -= csize; > > > > This seems to cause the modalias to be improperly constructed. As a > > consequence, automatic module loading at boot time is now broken. I > > think the reason why this fails is because vsnprintf() will skip all > > alpha-numeric characters after a call to pointer(). Presumably this > > is meant to be a generic way of skipping whatever specifiers we throw > > at it. > > > > Unfortunately for the case of OF modaliases, this means that the 'T' > > character gets eaten, so we end up with something like this: > > > > # udevadm info /sys/bus/platform/devices/54200000.dc > > [...] > > E: MODALIAS=of:Ndc<NULL>Cnvidia,tegra124-dc > > [...] > > > > instead of this: > > > > # udevadm info /sys/bus/platform/devices/54200000.dc > > [...] > > E: MODALIAS=of:NdcT<NULL>Cnvidia,tegra124-dc > > [...] > > > > Everything is back to normal if I revert this patch. However, since > > that's obviously not what we want, I think perhaps what we need is a > > way for pointer() (and its implementations) to report back how many > > characters in the format string it consumed so that we can support > > these kinds of back-to-back strings. > > > > If nobody else has the time I can look into coding up a fix, but in the > > meantime it might be best to back this one out until we can handle the > > OF modalias format string. > > Or just use 2 consecutive snprintf calls > > csize = snprintf(str, len, "of:N%pOFn", dev->of_node); > csize += snprintf(str + csize, len - csize, "T%s", > dev->of_node->type); Yeah, that's what I ended up doing. Rob came up with another alternative which is to output the 'T' via %c, which also works around the issue. Thierry
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